The sport of water skiing has become extremely popular and is normally conducted by towing a person upon water skis. Generally a tow line affixed to the stern of the motor boat is grasped at an outer end thereof by a person upon water skis so as to be towed across the surface of a lake or the like. While this sport has gained wide spread acceptance, it is generally recognized that a number of substantial dangers are involved in the exercise thereof. Aside from the natural physical danger of falling or the like, the skier experiences further danger of possible injury by other boats cruising in the same area as the skier's activities. While there is relatively small likelihood of collision between a boat and a skier being towed upon the surface of the water, there is substantial danger of a fallen skier being run over by another motor boat whose pilot was unaware of the skier's presence in the water. This danger has led to the passage of laws requiring the presence of an observer in the stern of a ski boat towing a water skier. It has become common practice for the observer to signal the release of a tow line by a skier by the observer raising his arm.
In water skiing, it is inevitable that a majority of the skiers will eventually fall from their skis or be forced to release the tow line whereupon they will ultimately sink into the water. The presence of the skier in the water is not normally hazardous per se, either because the skier is a good swimmer or is wearing a floatation jacket. However, events do occur which place the skier in the precarious position of being relatively invisible to the operators of other boats in the area. A downed skier at or beneath the surface of the water is very difficult to observe by a motor boat operator particularly if the boat is being driven at a substantial speed which causes the bow of the boat to rise up from the water and obstruct the operator's view of the surface of the water immediately in front of the boat. This danger is particularly real in congested or crowded lakes and the like and substantial and numerous tragic accidents have occurred because of this sequence of events.
The problem of the fallen skier has been recognized over time and diverse attempts have been made to provide water skiers with automatic warning devices. For instance, there are several U.S. patents which show devices which are attachable to the body or head of a water skier for the purpose of raising a flag or the like when the skier falls. Certain limitations inherently arise from this general approach to the problem. For example, the height of any warning device that may be raised above a fallen skier is limited and the visibility of such warning devices can be seriously impaired when the skier is disposed in other than a vertical position in the water.
The present invention operates to provide a solution to this problem by automatically raising a warning flag on the tow boat immediately after the skier releases the tow line but regulated in a unique way to prevent false signals therefrom. In current practice, those operating tow boats have become particularly vigilant of other boats in its area, particularly looking for warning signals. The present invention, as will appear, takes particular advantages of this practice by providing a warning signal which appears upon the tow boat rather than upon the fallen skier.
Several devices and systems, as will hereinafter be described, have been proposed from time to time to automatically accomplish the observer's duties. By far, the most common technique relies solely on the observer. In many instances, observers are very conscientious and attentive to their duties. However, due to the relaxed nature, and partying that is sometimes associated with water activities, some observers are less attentive than they should be. Further, when an observer is holding the warning flag up, his usefulness in accomplishing other tasks, such as helping to pick up the fallen skier, is negated.
As mentioned above, several prior art devices and systems have been suggested to facilitate the use of a warning flag when a water skier goes down.
For example, U.S. Pat. Nos. 3,786,778; 4,090,468; and 4,122,796 all relate to flag raising mechanisms that are operated by the observer, or the boat's pilot, to raise and hold the warning flag in the up position when the skier goes down.
Another prior approach is shown in U.S. Pat. No. 3,798,631 which discloses an alarm system which is automatically triggered to produce an audio and/or visual warning when the skier goes down. When the audio alarm is produced, a warning flag must be placed into a special socket to shut off the audio alarm.
Others, such as U.S. Pat. Nos. 3,602,188 and 3,735,724, disclose a system for automatically raising a warning flag when the skier's weight on the tow line is released.
While each of the foregoing prior art devices accomplish, in varying degrees, the purpose of the present invention, they fall short of being totally satisfactory, or desirable, in a number of respects. Thus, the manually operated devices described in U.S. Pat. Nos. 3,786,778; 4,090,468; and 4,122,796, all rely on the attentiveness of the boat's observer, and can be only as reliable as the observer. The semi-automatic prior art device described in U.S. Pat. No. 3,798,631 and the fully automatic devices of U.S. Pat. Nos. 3,602,188 and 3,735,724 are all relatively complex and costly mechanisms and increase the risk of being rendered inoperative because of mechanical failure. Further, U.S. Pat. Nos. 3,602,188 and 3,735,724 are inherently capable of giving both false "positive" and false "negative" signals and in so doing, defeat the integrity of the warning system.
Therefore, a need still exists for a reliable and relatively simple safety alert device for use on boats which tow water skiers and it is toward fulfilling that need that the device of the present invention is directed.